Transcranial Doppler (TCD) is a form of ultrasound. You may already be familiar with ultrasound technology because of its wide range of uses in diagnosing medical conditions and in monitoring during pregnancy. Transcranial Doppler is ultrasound that is performed at the base of the brain to assess the risk of stroke.

How Does It Work?

During Transcranial Doppler ultrasound, a hand-held wand called a transducer is moved over the skin near your temple. The transducer emits sound waves that then bounce off blood cells and are picked up again by the transducer. A computer interprets these sound-wave signals. TCD can provide your physician with information about the speed of blood flow in the brain. To assess stroke risk, the TCD technician or nurse may pass the wand over the carotid arteries (arteries in the neck) and arteries at the base of the brain.

How Is It Performed?

TCD does not require preparation on the part of the patient. You will be asked to lie down on an examining table or sit upright. The health care professional performing the TCD will apply a harmless gel to your skin over your temple to help the sound waves transmit into the body. Then the person who is conducting the test will pass the transducer over your skin.

Is It Safe?

There are no known harmful effects of ultrasound.

Questions to Ask Your Doctor About Transcranial Doppler (TCD) Tests

The following questions can help you talk to your physician about a transcranial Doppler (TCD) test. Consider printing out or writing down these questions and taking them with you to your appointment. Taking notes can help you remember your physician’s response when you get home.

• Am I at high risk for stroke?
• What can transcranial Doppler tell us about my risk for stroke?
• What happens next if the TCD test reveals a potential problem with the arteries leading to my brain?

Please print this list of questions here. Take them with you to the doctor and share them with friends and loved ones when you are encouraging them to see their doctors.